Description: This tiny crustose lichen with spherical perithecia for discs, grows on damp, sheltered siliceous rocks often close to some source of base influence (limestone or similar). It has a green-grey thallus and distinctive perithecia which are pale orange-brown above and sometimes grey at the base. It can be overlooked for the red-orange more vibrantly coloured P. lectissima which has three-septate spores compared with six- to seven-septate, narrowly ellipsoid spores in P. alhesiana. In Ireland, the species has not been seen for many years.

Key Identification Features:

• Pale orange-brown perithecia containing six- to seven-septate spores
• Damp, sheltered rocks often near rivers.

Original text submitted by Vince J. Giavarini

Distribution Map from NBN: Porina ahlesiana at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Porina ahlesiana at iNaturalist World Species Observations database.